Plasmas that are used in industry are commonly generated by ionizing a gas in a vacuum chamber. For example, a gas can be introduced into an evacuated plasma chamber where the work-piece is located. A strong electric field can be applied to the plasma chamber. The gas can form a plasma in an excitation region by undergoing an electrical breakdown under the influence of the strong electric field.
The electric field in such chambers is typically either capacitively or inductively coupled to the gas to remove electrons therefrom. In capacitively coupled plasma generators, the electric field can be applied between electrodes on opposing sides of the chamber. In inductively coupled plasma generators, the electric field can be applied to a coil surrounding the chamber, as but one example.
Plasma tools are commonly used in the fabrication of semiconductor devices. For example, plasmas are used to deposit materials on and etch materials from work-pieces to form specific electronic components on the work-piece substrate. However, many plasma tools in the semiconductor industry suffer from relative low density and unstable working conditions.